Process of treating rawhide.



UNITED STATES PATENT OFFICE.

ROBERT OROASDALE, OF SYRACUSE, NEW YORK.

PROCESS OF TREATING RAWHIDE.

, SPECIFICATION forming part of Letters Patent No. 683,728, dated October 1, 1901. Application filed August 31,1900. Serial No. 28,710. (Specimens) To all whom, it may concern:

Be it known that 1, ROBERT CROASDALE, of Syracuse, in the county of Onondaga, in the State of New York,have invented new and useful Improvements in Processes of Treating Rawhide, of which the following, taken in connection with the accompanying drawings, is a full, clear, and exact description.

This invention relates to improvements in the process of treating rawhide for the purpose ofrendering it waterproof, and rendering it in such a condition as to free it from contraction and expansion when in contact with moisture or dry air and at the same time make it translucent, so that it may be manufactured into articles of commerce.

Heretofore articles of rawhide have been objectionable owing to the fact that no means have been provided to prevent undue contraction or shrinkage when in a dry temperature or great expansion in a moist temperature in view of the fact that the hide in its natural state is so susceptible to the elements.

My object is therefore to so treat rawhide as to render it practically impervious to the moisture, and thereby free from contraction and expansion, and preserve its natural color preparatory to its being manufactured into Various articles of commerce; and to that end my invention consists in the several steps which constitute all of the process hereinafter described, and specifically set forth in the claims hereunto annexed.

In carrying out the process I first scour the hide on both sides in the usual way, removing the hair, "foreign substances, and fleshings from it, then cleanse by washing, so as to remove all acids and alkalies. Second, I then place the hide in a bath comprising the following solution: soft water, one thousand parts, by weight; salicylic acid, two parts, by weight; picric acid, three parts, by weight; boric acid, twenty-five parts, by weight, and allow it to remain there three or four hours. These acids all work conjointly upon the tissues of the hide to prepare it for the final bath hereinafter set forth. The salicylic acid hardens the tissues, the picric acid shrinks the hide by changing the form of the cells, or

rather elongates or flattens them, thereby making them transparent and at the same time restoring the natural amber color of the hide, while the boric acid cleanses the tissues and better prepares them for the final bath.

Third, I stretch the hide and place it in a current of warm air until partially dried. I then sponge both sides of the hide in a dark room, or in one in which the light is diffused similar to-a photographers dark room, with a solution of bichromate of potash compris- 6o ing one hundred parts, by weight, of soft water and two and one-half parts of bichromate of potash. The hides absorb a portion of the solution and when exposed to the light the action of the light on the bichromate of potash causes the tissues to become indurated or hardened and impervious to moisture and at the same time causes the hide to assume an amber color.

Having described my invention, what I 7o claim, and desire to secure by Letters Patent, 1s-

1. The herein-described process of preparing rawhide for manufacturing purposes consisting of the following steps: first, removing all hair, foreign substances and fieshings from the hide; second, saturating in a bathcomprising a solution of soft water, salicylic acid, picric acid and boric acid; third, drying the hide after this solution and then ap- 8o plying a solution of bichromate of potash, in a room in which the light is diffused and then exposing to the light.

2. The herein-described process of prepar- V in g rawhide for manufacturing purposes con 

